MG4 Rear Brake Discs corroded, 3700 miles in, + bonus other issues

[snowyy]

We are not that far away from being able to completely remove friction brakes from an EV. Yes It might be a controversial comment, but with developments in regen and the amount of retardation this can produce, friction brakes are becoming more and more unnecessary. They are really a legacy from ICE cars.
A soon as the regen technology develops a little more and it becomes commercial viable we will see them disappear.

Like driverless driving I don't think so. There's always an emergency stop to be had.

All ways wondered how are the discs protected from corrosion whilst they are waiting for a buyer?

 

[BananaDuck]

Took my car to dealer this morning for the R33 upgrade and fix for driver awareness feature plus other bits.

I was noticing that the parking brake was binding and I was hearing a scoring noise when braking. Just had call to say that both rear discs are significantly corroded and will need replacement. My car has 3700 miles on the clock, luckily I have an excellent dealer and they will get done what needs to be done. Still shocking to me though.

I know there are other threads covering my other issues but thought I'd update in this post as dealer has updates on these.

1. Rumbling/vibration - my car was not balanced correctly when it left factory, 3 of 4 wheels significantly out. Had re balanced twice, once at my cost, better but still not right. Test drive with engineer this morning, and then test drove the demonstrator which was even worse than mine! Dealer agrees that tyres are the likely cause and they will come back to me next week with a proposal, dealer agrees car not satisfactory in current state.

2. Passenger door lock has failed meaning that button does not work to unlock. Needs new handle.

3. Drivers foot rest broken. Temp repair by tech is very good, waiting for replacement.

4. LKA still dangerous and has to be switched off every time after restart. Tech is of the opinion that there will be no further update to this and the functionality is intentional. I'm not at all happy with that, action by me yet to be determined.

5. Scheduled charging broken. We hope fixed by R33 update but not tested yet.

6. Cannot preheat car while plugged in. Known issue, acknowledged by MG but no date for fix communicated.

As an interesting aside, there was another Trophy in for R33 update today with mine. Tech told me that new breather fitted but started leaking again, he wasnt sure what the fix will be.

The only reason I haven't rejected my car is that the dealership are so good with me. I feel that we can get the problems resolved and I would like to as I like the car. I honestly don't think I will ever buy another MG though, not because of my dealer, because of MG and how they handle things. Tech told me today that if he has an issue with Nissan (other marque they deal with) then he gets a reply often within the hour but always quickly, MG can take days and need frequent chasing and often don't provide solution or an ETA for it.

Hammonds dealership 9.5/10 from me, MG a generous 1/10

Hello, please could you tell us if the dealer charged you for the new rear discs and pads?

 

[Bandanaman]

Like driverless driving I don't think so. There's always an emergency stop to be had.

Very True, whilst in an ideal world there would be a solution found to enable the KERS system to work in all curcumstances there will always be a need to provide an emergency breaking system of some kind that relies on a mechanical function rather than electrical, so I dont see your disc's and pads going anywhere for a long time yet...

 

[Deleted member 9692]

Hello, please could you tell us if the dealer charged you for the new rear discs and pads?

Hi, they haven‘t yet been fitted. They have been ordered and I am not paying.

 

[Lovemyev]

Hi, they haven‘t yet been fitted. They have been ordered and I am not paying.

Did they order brake pads as well, because they will be worn out, given how long it will take to get the discs here .
( of course they will get replaced at the same time, I hope ! ).

 

[Deleted member 9692]

Did they order brake pads as well, because they will be worn out, given how long it will take to get the discs here .
( of course they will get replaced at the same time, I hope ! ).

Yup, all in hand. I have a few other bits to be done, replacement passenger door handle, drivers foot rest and the discs and pads will all be done together.

 

[john andersen]

Very True, whilst in an ideal world there would be a solution found to enable the KERS system to work in all curcumstances there will always be a need to provide an emergency breaking system of some kind that relies on a mechanical function rather than electrical, so I dont see your disc's and pads going anywhere for a long time yet...

touch the brake pedal at the same time as the go pedal and you will get an experience of your life
if it will brake with all it has!

 

[BananaDuck]

Hi, they haven‘t yet been fitted. They have been ordered and I am not paying.

Thanks for the update.
I'm stunned, I never ever come across a dealer that would even consider doing that for free.
I've had issues with my Honda e and appalling service, if you can call it that from them from the moment I contacted them to buy it, maybe I should have taken notice of the alarm bells at the time and walked away.

Anyway, not all EV's have minimal rear brake wear, my Honda had done less than 17k miles after it's second service about 6 months ago and the front brakes quoted as 10% worn with 10mm left on the pads, with the rear 30% worn at 7mm on the rear pads. I suspect the excessive rear brake wear is one reason the e is so bad on efficiency compared to other EV's. My theory is that ACC is the main cause of this excessive wear.

 

[Deleted member 9692]

Thanks for the update.
I'm stunned, I never ever come across a dealer that would even consider doing that for free.
I've had issues with my Honda e and appalling service, if you can call it that from them from the moment I contacted them to buy it, maybe I should have taken notice of the alarm bells at the time and walked away.

Anyway, not all EV's have minimal rear brake wear, my Honda had done less than 17k miles after it's second service about 6 months ago and the front brakes quoted as 10% worn with 10mm left on the pads, with the rear 30% worn at 7mm on the rear pads. I suspect the excessive rear brake wear is one reason the e is so bad on efficiency compared to other EV's. My theory is that ACC is the main cause of this excessive wear.

It's not excessive wear, it's severe corrosion, presumably from not getting used much and previously sitting in a compound for many months

 

[tsedge]

It's not excessive wear, it's severe corrosion, presumably from not getting used much and previously sitting in a compound for many months

Yes, I think they are poor at protecting the car in transit/storage

 

[BananaDuck]

It's not excessive wear, it's severe corrosion, presumably from not getting used much and previously sitting in a compound for many months

I know that your issue is severe corrosion, I'm flabbergasted that they'd even entertain doing anything for free with my experience of car dealerships, let alone actually replace them for free. At best I would have thought that they might clean them up & grease where applicable to get them operational.
Brake pads & discs are wear & tear consumables so it looks like you've been extremely fortunate to get the work done for free.
If they were like this due to sitting in a compound for many months (like many new cars do), then it should have been abundantly clear at the pre-delivery inspection there was an issue or even as you drove off the forecourt. I had a courtesy Honda e a few weeks ago whilst mine was in for another failed attempted fix and that courtesy car had been sat for a long time because the brakes were stuck on and it skidded/skipped and juddered excessively in the car park for 50m until they freed off, then they were fine for the couple of hundred miles I did in the car before returning it.
The reason that I stated my wear is to show that brake wear is not always minimal on all EV's.

 

[Robert Gardner]

They haven’t worn out. The discs are corroded.

I have the same issue when I go away on holiday and leave I come back to rusty discs and tales a lot to wear of the surface rust, today I have had to have a wheel off and the discs are scored ( I have been in the Motor Industry as an Area Manager for w Car Manufacturer so I know the quality of the Materials being used is poor just as well the car was cheaper than its competitors. Has anyone found a brake Calliper and discs of better quality.

 

[stevegus]

touch the brake pedal at the same time as the go pedal and you will get an experience of your life
if it will brake with all it has!

The ABS will kick in as the tyres break traction

 

[Lovemyev]

Has anyone found a brake Calliper and discs of better quality.

I had a quick look last week and I could not find any third party discs available yet.
Unless somebody else knows differently ???.

 

[Macadoodle]

Have now stripped the brakes on all four corners and found every one needed rubber grease stuffed into the sliding pin rubbers (totally dry) and a proper amount of copper grease on the pad contact surfaces.
The rear discs are now beginning to take on a more even appearance, with the 'missed border' effect wearing off bit by bit, and the parking brake no longer sticks on.
A good tip to achieve this is slip it into neutral now and then and apply the brakes, there will be no regen when not in drive and the rear pads will get the best workout the car can give.

 

[tsedge]

Have now stripped the brakes on all four corners and found every one needed rubber grease stuffed into the sliding pin rubbers (totally dry) and a proper amount of copper grease on the pad contact surfaces.
The rear discs are now beginning to take on a more even appearance, with the 'missed border' effect wearing off bit by bit, and the parking brake no longer sticks on.
A good tip to achieve this is slip it into neutral now and then and apply the brakes, there will be no regen when not in drive and the rear pads will get the best workout the car can give.

Very useful, thanks. We need an "DIY guide to MG4 Maintenance"!